Yes, it can take a long time on most any bus. Invest in a powerbank to charge your phone, and get headphones/bluetooth.
Outside of San Francisco, I've never seen violence on a bus personally, but plenty of crackheads. I'm a big guy, so they don't pick me to mess with, but seen others harrassed. Also seen theft. DO NOT reorganize all your stuff on the bus between a stretch of stops, and have your purse strapped to you and not just sitting next to you. Being careless attracts problems. If I worry about falling asleep on a bus, I'll loop my backpack around a leg so it doesn't dissapear by time I wake up.
